The present invention relates to the field of computer graphics, and in particular to methods and apparatus for specifying contact deformations of computer graphics objects. Many computer graphic images are created by mathematically modeling the interaction of light with a three dimensional scene from a given viewpoint. This process, called rendering, generates a two-dimensional image of the scene from the given viewpoint, and is analogous to taking a photograph of a real-world scene. Animated sequences can be created by rendering a sequence of images of a scene as the scene is gradually changed over time. A great deal of effort has been devoted to making realistic looking rendered images and animations.
Contact between objects is natural in the real world but is often avoided in three-dimensional computer graphics and animation. One reason for this is the difficulty in modeling the deformations of soft objects due to collisions. Collision simulations can simulate the deformations of soft objects in response to collisions; however, these simulations are often time-consuming, especially if they take into account features such as volume preservation, ballistics, bidirectional deformation feedback cycles between objects, and changes in deformation over time.
Computer graphics animators often prefer to work interactively, making incremental changes to an object, observing the results, and then making further changes until they are satisfied with the aesthetics of the object. Because accurate collision simulations are so time-consuming to execute, animators often must wait minutes or hours to observe the results of their changes. This disrupts the animators' interactive workflow and makes fine-tuning the aesthetics of soft-body collisions a frustrating and time-consuming process. As a result, animators often make acting decisions that minimize or eliminate contact between deformable objects, such as character models, and their environment. This makes the animation look detached from its environment.
Therefore, there is an unmet need for a system and method of interactively deforming objects in response to collisions and contact. There is also an unmet need for the system and method to give users fine control over the shape and other aesthetic characteristics of the contact deformation of an object. There is also an unmet need for a system and method of interactively deforming objects to be applicable to a wide variety of different types of objects and collisions.